1. Field of the Invention
This invention relates to a power transmission device mounted to a vehicle such as an automobile. Specifically, the power transmission device is a transaxle or the like equipped on a hybrid vehicle.
2. Description of Related Art
In a vehicle like a hybrid vehicle which runs with the engine being at rest, an electric oil pump is usually provided in addition to the mechanical oil pump for generating the hydraulic pressure of the transmission. (Refer to Japanese Patent Application Publication No. 2012-13202 (JP 2012-13202 A), for instance.)
In JP 2012-13202 A, a discharge passages of the mechanical oil pump and of an electric oil pump are merged before being connected to a hydraulic circuit. An oil temperature sensor is provided in the passage downstream of the merging section. Further, a check valve is provided in the discharge passage of the electric oil pump.
In the above JP 2012-13202 A, relative location in vertical direction regarding each of both the oil pumps, the oil temperature sensor, and an oil-introducing portion of the hydraulic circuit is, referring to FIG. 1, such that both the oil pumps are disposed vertically lower than the passage downstream of the merging section, and that the oil temperature sensor and the oil-introducing portion of the hydraulic circuit is at almost the same height in vertical direction.